It is also revealed that Carrie Tolstedt, whom critics say skimped on her oversight duties, stepped down from her position as head of the community banking division in July.

September 20: Stumpf testifies before the Senate Banking Committee, where Sen. Elizabeth Warren (D-Massachusetts) turns her wrath on the bank figurehead. Observers call it an evisceration, beatdown, and smackdown.

September 21: Dozens of ex-employees say Wells Fargo suppressed whistleblowers by firing them in retaliation, substantiating lawmaker suspicions the bank emphasized sales and profit margins at the expense of ethical behavior.

Confidence in Stumpf’s leadership wavers, with some people saying he’s being reactive instead of proactive. The bank bleeds billions in market value.

September 29: Stumpf faces a fresh wave of outrage from lawmakers while testifying before the House Financial Services Committee, who say he buried key information regarding the scandal from the board. "We should have done more sooner," he says.

October 12: Stumpf finally steps down as CEO and chairman, "retiring" from both posts immediately. COO Tim Sloan, a Stumpf ally, takes over as CEO.

Hit or miss?Miss - Wells Fargo’s response further angered an American public still wary of banking institutions with a series of anodyne talking points that didn’t address the problem. Its reputation will suffer long after its bottom line has bounced back.

TakeawaysLesson 1: Demonstrate your company’s culture and values. Don’t tell the public a scandal is an isolated incident as reports emerge your company suppressed whistleblowers and disclosed only the minimum legally required of it.

Lesson 2: Be transparent and proactive. Better to put out a couple of blazes here and there than wait for a firestorm.